Thread-controlling machanism for sewing machines



"A. 9mm. THREAD CONTROLLING MECHANISMFOR SEWING MACHINES.

APPLICATION FILED FEBX YI I920.

Patented Oct. 24, 1922.

2 SHEETSSHEET I.

INVENTOR ATTORNEY A. GRIEB. THREAD IONTROLLING M ECHANISM FOR SEWING MACHINES.

APPLlCATlON FILED FEB. 7, 1920. 1 $133,000.

Patented Oct. 24, 1922.

2 SHEETSSHEET Z.

12* I l 54 M H WITNESSS:

Patented Get. 24, 1922.

I thence same stares mam creme.

ALFRED GRIEIB, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO THE SINGER MANUFAC- TUBING COMPANY, OF ELIZABETH, NEW JERSEY, A CORPORATION 013 NEVT JERSEY.

THREAD-CONTROLLING MECHANISI I FOR SEWING MACHINES.

Application filed February 7, 1920. Serial No. 356,833.

To all whom z'tmmy concern. v q

Bev it known that I, ALFR n Game, a citizen of the United States, residing atElizaboth, in the county of Union and State of NewJersey, haveinvented certain new and useful Improvements'in Thread-Controlling Mechanisms for Sewing Machines, of which I the followingis a specification, reference being had therein to theaccompanying draw ings.

thereof, a looper which passes a loop of a second thread through the needle-loop at the I under side of the work, and an overedge implement or second looper which, in one form,-

seizes the looper-loop and carries it over the edge of the work and into position for entry by the needle at the upper side: of-thework or, in another form, passes a loop of a third thread through the looper-loop and presents said loop or" the third thread to the needle above the work.

Innmachines of the above type, as the needle descends through a previous looper loop presented to it at the upper side of the work, it tightens the previous need1e-loop and snubs it around limbs of'a looper-loop at the under side of the work sothat, as the looper moves forwardly in entering a new needle-loop, the looper-thread is bent sharply around the previous" needle-loop. As the forward movementof the looper is depended upon to tighten the previous looper-loop, it will be readily appreciated that a heavy tension must be applied to the looper thread in order that the looper in its forward movement can pull the sharply bent looper-thread through the previously tightened needle-loop. In overedging bags with rough and easilywbroken threads, such as,

This invention rrelates to overedge sewset the looper-loops without necessitatingthe application of a heavy tension to the looper thread or threads thus adapting the ma-' chine to the handling of rough and easily broken threads.

Another object of the invention is to provide 'overedge stitch-forming mechanism which will operate to form and set the stitches, while avoiding a weakening of the sewing threads incident to a harsh reeving or sawing action of one thread against another. i

According to the present improvement, a

looper-thread take-up or stitch-tightening implement of special construction is combined with the needle and looper. This implement, while moving in opposition to the advancing looper, seizes the looper thread between the looper-eye and the tightened needle-loop and pulls the slack looper-thread from the previous looper-loop in nearly a straight line through the needle-loop, thus avoiding the reeving and locking action incident to tightening one thread while it is bent sharply about another thread. In the.

embodiment of the invention illustrated, the

stitch-tightening implement is combined with a looper which advances in a path inclined forwardly toward the line of feed.

This implement seizes the looper-thread close to the previous needle-loop and thereby serves to draw the looper-thread substantially straight or at a very obtuse angle through the needle-loop. The present stitch-tightener is also combined with the second looper or spreader but isv actuated from its own eccentric on the main shaft of the machine, whereby a close timing of its movements may be secured relative to the movements of the spreader, in order that the looper thread maybe given up as it is required by the spreader during the first part of the lift of the latter, thus avoiding an undue straining of the looper thread while maintaining it closely under control. The timing of the present stitch-tightening im plement is preferably such that it seizes the stitch tightener withdraws as the second looper or spreader cooperates with the looper. The withdrawal of the stitch-tightener is timed so that the looper thread is maintained under control but is not subjected to undue strain.

In the accompanying drawings, Fig. 1 is a fragmentary frontside elevation of a machine embodying the invention. Fig. 2 is a fragmentary front end ele-vation of the machine. Fig. 3 is a plan view of the parts below the throat-plate; the latter being shown in dotted lines. Figs. {1 to ,;inclusive, are bottom plan views "illustrating the action of the stitch-tightening implement and Fig. 8 is a'top plan view of the parts shown in Fig. 6.

In the specific embodiment of'tlie' inyention chosen fol-the purposes of the present disclosure,.l indicates the machine bed from which rises the standard 2 of thebracket arm 3 terminating in the hollowhead 4"101' the usual reciprocating needle-bar 5 and twin pressei'bars 6-6; the former carrying the eye-pointed needle 7 and the latter the presser-feet' 8 -.8. Supported at an elevation above the bed 1', upon the bearing standards 9 9. is the cloth-plate 10 into which is letv the usual throat-plate 11 having the slots through which the feed dog sections 130perate in a manner well known. The throatplate 11 is also formed with the usual needleslbt 1a and stitch tongue 15.

Cooperating with the needle ,7 is the thread-carrying looper l6'which is oscillated about the looper-shait 17 by means otthe usual pitman connection 1 7 with an eccentric 17 vuponthe main-shaft 5-. Since the lOODQ/I'.

eccentric 19 and pitman 19 needle, looper and spreader are ,otthe well shaft-1T is horizontally disposed and is inclined. forwardly toward the line of feed.

it renews that the pathohthe advancing loop'er isalso inclined forwardly toward-the line of teed. a

In the present instance, the l ooper. 16,

which is formed with the usuali-thread de livering eye 16, projects its loop through a needle-loop in rear of the needle 7 and moves beyond the edge of the work where the looper-loop is seized by the usual second looper or spreader 18 which, in the present instance, lifts the looper-loop over the edge of the work and presents it for entry by the needle 7 on the next descent of the latter. The spreader 18 is carried by one arm ofa bellcran k-lever which is pivote-dat 20 to the free end of a link 2l-the opposite end which turns about the downwardly, forwardly and outwardly inclined bearing pin 22 fixed in the lug 23 on the head The other arm 19 oftlie hel-lcrank-lever is con nected to the pivoted lever 19 which is ac-- tuated from the main shaft .9 by means o'i'the known construction disclosed, for example, in my Patent 1,234,159,0t Oct: 16, 1917, further description thereof is believed to The present invention resides more pa r ticularly in the take-up or loop-tightening implement 26 which'preferably moves trans-w versely of the line of feed in a horizontal plane'close to; the under side of the throatplat-e, as shown in Fig; 1. Referring now. to Fig. 3, it will be seen that the stitchtightening implement is adjustably mounted by means of'the slot'a'nd screw connection 27 upon the forwardly extended arm 28 of a lever pivoted upon-the 'verticalpin 30 located inrear of the needle and looper andfixed in a lateral lug lscrewed to the bearing standard 9. The other arm 3201 the stitchtightener leverfcarries-a ball 33 which is connected by means of a pitman 34-to-a ball-- eccentric 35 on the main-shaft 5.

The stitch tightener 26 is torkedatits free end to form a smooth surfaced throat '36,"

Figs. to 8, inclusive, which is moved" transversely of'the line of seam formation from one side to the otherside of-the line of needle punctures when viewed in'plan, as in F 4 to S, inclusive. When the. throat of the stitch-'tightener,reaches tlie line of needle puncturesrepresented by the tightened needle-loops n, 5, it' catchesor forms a bight'in' thelooper-thread tbetween theilooper-eye and the last tightened needle-loop at the'time the looper-eye is crossing'the line oi"ncedlepunctures or, other words, at the'time the "looper is enter ing' thenascent needle-loop a; As the stitchtightenermovesin a direction opposite'to thatin'whifzh the looper is moving, Fig.5, it pulls the bight o'f loop'enthre'ad away from the line'jottne'e'dle punctures and thus pulls the flooper-thread" t in nearly a straight line, or at" a very obtuse angle. throughthe previously tightened needle loop a. The path otn ovement of thethroat" of. the stitch-tightener in passing from one extreme position shown inFig. 4' to its other extreme position. Fig. 6. intersects the loop er-thread the position shown in Fig. 51 After the st-itch tightener engages theloopend of its path and iSQafCtiVBIQI moving totighten the previous"looper loop. By this action'the stitch tightener'assists in tightening the previously formed looper-loop Z neat er thread-it continues itsEmotiontoward the ly about the limbs of the newneedle-loop n" at the upper side of the work. The stitchtightener eccentric 85 is so timed relative to the spreader eccentric 19 that the stitch-' tightener 26, in moving from the position shownin Fig. 6, to that shown in Fig. 7,

will give up and releasethe looper thread If er is an important feature which permits a well formed stitch to be secured without iurduly straining. the looper-thread 1t Wlii be observed that at no time .18 there a stitch-tightening strain imposed upon one o.-

or at an acute angle about another sewing t read. Being mounted in rear of the looper, the present stitch-tightener and its operating mechanism do not'interiere with the threading-g ot the looper and require no special guards or covers to prevent contact ot' the work therewith.

While the above'descrihed timing of the parts is deemed preferable, the invention is not to be understood as limited to the exact timing described as it may bevaried more or less bythose skilled in the art, within the scope ofthe invention defined in the appended claims.

Having thus set forth the nature of the invention, what I claim herein is l. in a sewing ma hine, the combination with overedge stitch-forming mechanism. including a reciprocating needle a threadcarrying looper, of a stitch-tightening implement, and means for movng said implement in a direction contrary to the direction of advance of the looper, said implement acting to form a bight in the looper-thread leading from the eye of the looper to the previous needle-loop and move said bight of looper-thread away from the line of needle punctures.

9. Ina sewing machine, the combination with overedge stitch-forming mechanism including a reciprocating needle and a threadcarr ving looper, of a stitch-tighteningimplement, and means for moving said implement in a horizontal plane in a direction con-- trary to the direction of advance of the looper. to seize the looper-th nd loading from the eve oi the looper to the pi rious needle-loop and pull the slack loog'ienthrcad in the previous looper-loop through the previous needle-loop.

3. In a sewing machine, the combination with overeda'e stitch-forming mechanism including a reciprocating needle and a threadving looper, of a stitch-tightening implement pivotally mounted on a vertical axis in rear of the needle and looper, and means from the loop thesewing threads while it is bent sharpliy opposite to the direction of adance ol' the looper, to seize the looperread leading from the eye of the iooper to previous needle-loop and pull the slack er-thread in the previous looper-loop through the previous needle-loop.

l. in a sewing machine, the combination with overedge stitchatorming mechanism including a reciprocating" needle and a looper, oi a stitc -tightening implement, and means for moving implement from one side to the other side oi? the line of needle-punctures contrary to the direction of ofthe looper, said implement being positioned 1 timed to engasze the looper-thread lear to the last stitch duri the advance of the looper.

In a sewing machine, the combination with overedgestitch-forming mechanism in: eluding reciprocating needle and a looper, of a stitch-tightening implement, and means for moving said implement from one side to the other side of the line of needlepunctures contrary to the direction of advance of the looper, said implement being adapted to form a bight in the looper thread leading from the looper-eyeto' the last stitch and pull it away from the line of needle-punctures, thereby tightening the previous looper-loop.

6. In a sewing machine, the combination with overe Le stitch-forming mechanism in cluding a reciprocating needle and a loo per, of a stitch-tightening implement pivotaily mounted in rear of the needle and looper and adapted to engage the looper-thread between the looper-eye and the last stitch to as the looper in tightening the previous urge looper-loop.

In a sewing machine, the combination with overedge stitch-formingmechanism including a reciprocating needle and a looper, of a stitch-tightening implement pivotally mounted in rear of the needle and looper and forked at its extremity to engage the looperthread between the looper-eye and the last stitch substantially as and for the purpose specified.

8. in a sewing machine, the combination with overedge stitch-forming mechanism including a reciprocating needle and a looper, oi a stitch-tightening implement having a thread-engaging throat and means for moving said implement so that its throat moves from one s de to the other side of the line 01 needle-punctures at a position between the looper and the last stitch, said implement operating to seize the looper-thread and assist the looper intightening the previous looper-loop,

nections between the main-shaft and said loop 91' and overedge implement, a stitcl eg ntenin in'zpiement adn'oted to @110?! th ooper Aid between L- e looner-eye 18531 stitch, and an operative connection lie/tween the mnii'i-shnt't and said sti tightening implement, said last mentioned operative c mnoction being separate and distinct irom the ope itive connections between the main-shaft and the overedge implement,

whereby the stitch-tightener may be closely iimed relatively to said implement.

10. In sewing machine in combination, a reciprocating i'ieodle, a looper, an over-edge implement and a stitch-tig 'h nor adapted to engage the looper-thn-iad on ween the inopereye and the last l ch :1 main-shaft, an eccentric on said shaft and connections for operating;- the looper, e

on sad shaft and com itlbn i, for on crating:- said overedgg e implement, and

a third eccentric on said shaft and connections for one 'ating the stitch-'tlghtener.

11. In a sewing: machine, the crnnhinationj with overedge stitch-forming mechanism including a reciprocating needle and a thrernlcarrying looper of a stitch-tightening implement, and means for moving; said implement contrary to the direction of advance of the looper, said implement being constructed and arranged to engage and torm a hight in the looper-thread close to the pike vious needle-loop and pull the looper-thread at an abtuse angle through the previous loop, whereby the" previous loopery he tightenediunder a light tension.

12in a sewing; machine, the combination \vith; feeding mechanism and overedge stitch-forming mechanism including a reciprocating needle and a thread-carrying loop'er racing in a 'path inclined forwardly toward e line of teeth of a stitch-tightening implement, and means for moving said implement toengage the looper-thread and wall it at an obtuse ano'le throu 'h the orethe point of first engagement of said throat with the loop .l-thread, whereby said implement will continue its motion 'atter seizing the looper-thread and will be active in tighteni'ng'the prevous looper-loop.

In testimony whereof, I have signed my name to this specification.

ALFRED GRIF 

